Shaft bearing



June 14, 1927.`

M. HEMLEB SHAFT BEARING Fiied July 16, 1923 WI'INESSES I INVENTOR Zm/(IQ /(QM, BY`/ TTORNEY i Patented June 14, 1927.

UNITED STATES PATENT OFFICE.

MARTIN HEMLEB, OF ELIZABETH, NEW JERSEY, ASSIGNOR T THE SINGER MANU- FACTURING COMPANY, 0F ELIZABETH, NEW JERSEY, A CORPORATION 0F NEW JERSEY.

SHAFT BEARING.

Application inea my 1e, 1923. serial No. 651,802.

This invention relates to shaft bearings and has for an object to provide a selflubricating bearing or bearing bushing particularly adapted for a high-speed shaft,

such as the lower or hook shaft of a rotaryhook sewing machine. In sewing machines of the rotary-hook type, the hook-shaft commonly makes a plurality 4of revolutions for each complete reciprocation of the needle, which means that in a sewing machine making, say, 4000 stitches er minute, the hook shaft is making 8000 P. M. in a 2 to 1 machine or 12000 R. P. M. in a 3 to 1 machine. Thus the problem of bearing lubrication becomes im ortant if quiet'running and a satisfactory caring life are to be attained.

To the accomplishment of the ends in view, the bearing is referably made up in the form of a cylin rical bushing adapted to be inserted in a cylindrical bearing aperture in the machine frame. The bushing may comprise an outer or casing member and an inner or core member telescopically tted to the outer member. The core member is preferably formed at the upper side of its outer surface with a longitudinally extending oil-receiving and distributing roove and at the lower side of its outer surace with a longitudinally extending groove constituting an oil-pocket; the two ooves bein preferably. connected by a p urality of circumferential grooves in the outer surface of the core member. The oil is preferably fed from the oil-pocket to the shaft through a capillary slot cut through the `wa'll of the core member separating the oil-pocket from the inner or bearing surface of the bushing. The bushin is formed at its ends with internal circum erential grooves communicating with the oil-pocket groove and serving to catch any oil thrown from the shaft at the ends of the bearing and return it to the pocket. i.

In the accompanying drawings, Figf 1 is a longitudinal vertical section of the shaft bearing as applied to a rotary-hook sewing machine. Figs. 2 and 3 are, respectively, side elevation and ytop plan views of the casing member of the bearing.

Figs. 4 and 5, are, respectively, side elevation (partly in section and top plan views of the core member. .`ig. 6 is a horizontal section through the core member on the line y I3 for the reciprocating needle 4 which cooperates With the rotary hook 5 t0 form stitches. The hook 5 is carried by a hookshaft 6 which is journaled in the bearing aperture 7 of a special bearing bushing sustained by the frame lug 2.

The bearing bushing may `comprise an outer or casing member 8 and an inner or core member 9 which, preferably, is snugly fitted telescopically to the casing member, as by a light driving fit. The casing member, when used, may 'have the form of a Simple sleeve provided at its upper side with an -oil-hole l0 Vadapted to register with an oil-supply duct 11 in the machine frame.

The core member 9 is preferably of hollow cylindrical form having the inner bearing surface 7 at the ends of which are formed the internal circumferential oil-catching grooves 12, 12 which communicatethrough the apertures 13, 13 with the oil-pocket groove 14 eXtendin Jlongitudinally of the core member 9. T e oil-pocket groove is preferably filled with a strip of felt 15l or other oil-absorbent material and is 4separated from the bearin aperture 7 by a 'relatively thin wall 16, Fig. 8, through which is cut a fine capillary'slot 17 extending longitudinally and centrally of the reservoir groove 14. f

The core member 9 is formed opposite the oil-pocket groove 14 with a longitudinally extending oil-receiving and distributing groove 18 which is connected to the pocket groove 14 by means of the circumferential grooves 19. A. screw 20, Fig. 1, may be employed to fix the core and casing members in assembled relation. The apertures 21 in the extreme ends of the bear ing member 9 are shaft clearance apertures and are preferably made a little larger than the shaft so as not to 'touch the latter.

The lubricant is supplied to the bearing through the duct 11, whereupon. itdistributes los itself along the upperJ longitudinall groove 18 and runs down the circumferential oilfeeding grooves 19, quickly and evenly saturating the absorbent strip 15 in the groove 14, which, when the bushln is in working position and suitably encase constitutes an oil-reservoir. When the machine is in operation the lubricant is drawn upwardly frm the reservoir throu h the capilla-ry slot 17 and is evenly distri uted as a thin film between the shaft and bearing walls. As the oil works out at the ends of the bearing it is thrown oli by the shaft into the internal oil-receiving grooves 12 which return it to the reservoir 14 without permitting escape of oil through the shaft openings 21.

The present bearin will run for long periods without replenishment of the lubricant supply and is simple in construction and easy to assemble with the machine. It constitutes .a unit which may be removed from and replaced in the machine in the same manner as an ordinary bearing bushing, yet it is self-lubricating; the oil repeated y traversing a circuit from the supply reservoir to and between the bearing surfaces and back .to the supply.

It will be apparent that the sleeve-element 8 may be omitted by fitting the core element directly to a bushing aperture in the machine frame.

Having thus set forth the nature of the invention, what I claim herein iss- 1. A bearing bushin comprisin a sleeve formed in its outer sur ace with a epression constituting an oil-pocket, and separate capillary oil-supply and gravity return ducts connecting said pocket with the inner or bearing surface of the bushing.

2. A bearing bushing comprising a onepiece cylindrical body formed with an external depression constituting an oil-pocket, an internal bearing aperture, and a capillary oil-supply duct leading through the wall of said cylindrical b y from said pocket to said bearing a rture, said cylindrical body having interna circumferentially extending oil-catching grooves Within its ends and gravity oil-return ducts leading from said grooves to said oil-pocket.

3. A bearing bushing comprising a sleeve having an inner bearin surface, an outer surface formed with a epression constituting an oil-pocket, and a capillary duct cut through the wall of said sleeve and connectf ing the oil-pocket with the inner bearing surface, said sleeve also having (gravity oilreturn ducts within its ends lea ing to said oil-pocket.

In testimony whereof, I have signed my name to this specification.

MARTIN'HEmiEB. 

